1. Field of the Invention
The present invention relates to a pressure control valve, for example, a pressure control valve which is used in a car air conditioner or the like, and is provided with a pressure response element constructed by a diaphragm or the like.
2. Description of the Conventional Art
As this type of pressure control valve, in conventional, for example, there has been known a structure as shown in the following Japanese Unexamined Patent Publication No. 7-332807. The pressure control valve is provided with one pressure chamber (in which a gas having a comparatively great thermal expansion coefficient is enclosed) in which an internal pressure is changed in response to a temperature change of a certain specific position, the other pressure chamber in which an internal pressure is changed in response to a temperature change of a refrigerant, a diaphragm for comparting the one pressure chamber and the other pressure chamber, a valve body for changing a valve opening degree in connection with a displacement of the diaphragm, a coil spring for energizing the valve body, and the like. The valve body is structured such as to be displaced to a position where the internal pressure of the one pressure chamber, which acts in such a direction as to make the valve opening degree large, balances with the internal pressure of the other pressure chamber and the energizing force of the coil spring, which act in such a direction as to make the valve opening degree small.